A Small-Molecule Walker Ratcheted by Enzymatic Hydrolysis

Abstract

This work describes the design, synthesis and operation of a (R,R)-(+)-hydrobenzoin-diacetic acid molecular walker attached to polyether tracks containing 2, 3 or 4 secondary alcohol footholds. A macrocycle-the walker attached to a 2-foothold track by two ester linkages-was regioselectively hydrolysed by lipase AS. The resultant seco¬-acid was recyclised using Yamaguchi chemistry, demonstrating a bipedal walker stepping off, and on to, a track. These conditions were extended to tracks containing 3 and 4 alcohol footholds and the design of a 3-foothold track that incorporated a pentaethylene glycol chain. Using an information type Brownian ratchet mechanism, ~90% of walkers stepped away from the starting position, and ~68% of walkers took 2 steps to a foothold 16 atoms away. Importantly only smaller or equal to4% of walkers were found to completely detach from the track per operation cycle.

Date of Award	1 Aug 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Leigh (Supervisor) & Michael Greaney (Supervisor)